Our overall objective is to study mechanisms involved in the uptake of choline and the synthesis and release of acetylcholine (ACh). Using cortical synaptosomal preparations that are preincubated with (methyl) 3H) choline in order to effect the synthesis of labeled ACh, we will continue our study on the mechanism of action of beta-bungarotoxin, black widow spider venom and sulfhydryl reagents. We will initiate studies on the modulating activities of neuroactive peptides, on the source of choline for ACh synthesis and whether ACh is released from vesicles or cytosol.